| 1. |
- Dong, G J, et al.
(författare)
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Cold molecules in pulsed optical lattices
- 2005
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Ingår i: Progress in Quantum Electronics. - : Elsevier BV. - 0079-6727 .- 1873-1627. ; 29:1, s. 1-58
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Forskningsöversikt (refereegranskat)abstract
- We review recent theoretical studies on the dynamics of molecules in pulsed optical lattices. These lattices are periodic potential wells formed by the interaction between two counter propagating far-off resonant optical fields and the molecules. We show that the molecules can be manipulated in both constant velocity and accelerating lattices for a number of applications. We first study a molecular optical mirror through the reflections of molecules by a stationary optical lattice and show that the reflectivity can be significantly improved by optimizing the pulse duration. When reflection occurs from a moving lattice, we show that molecules can brought to rest when the lattice velocity is half the molecular velocity, demonstrating a new and efficient method for creating slow cold molecules. We further describe a microlinear accelerator for molecules produced by an accelerating optical lattice, which is achieved by frequency chirping one of the two optical fields. The molecules trapped by the potential wells of the lattice are accelerated to high velocities (10-100km/s) over micron-size distance within nanosecond time scales. When the lattice is decelerated, the trapped molecules can be slowed to zero velocity, offering an alternate method for producing slow cold molecules. Molecules that are not trapped in the accelerating lattice can be temporarily localized around a characteristic velocity,. which is uniquely dependent on the mass-to-polarizability ratio. We show that this feature can be used for a new form of time-of-flight mass spectrometry for chemical analysis of a mixture.
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| 2. |
- Dong, G J, et al.
(författare)
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Super-Gaussian mirror for high-field-seeking molecules
- 2005
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 72:3
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Tidskriftsartikel (refereegranskat)abstract
- A matter wave mirror using a single, pulsed, super-Gaussian (SG) optical beam for specular reflection of neutral ground-state molecules is studied. The mirror has a high reflectivity close to 100% and nearly perfect specular reflection over a large incident angle. This mirror avoids the usual problems due to surface roughness and the van der Waals interactions that occur in conventional atomic mirrors. Further, it is capable of reflectance and transmittance with applications to velocity filtering and deceleration of cold molecules.
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| 3. |
- Höglund, Carina, et al.
(författare)
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Stability of (B4C)-B-10 thin films under neutron radiation
- 2015
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Ingår i: Radiation Physics and Chemistry. - : Elsevier BV. - 0969-806X .- 1879-0895. ; 113, s. 14-19
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of (B4C)-B-10 have shown to be very suitable as neutron-converting material in the next generation of neutron detectors, replacing the previous predominantly used He-3. In this contribution we show under realistic conditions that (B4C)-B-10 films are not damaged by the neutron irradiation and interactions, which they will be exposed to under many years in a neutron detector. 1 mu m thick (B4C)-B-10 thin films were deposited onto Al or Si substrates using dc magnetron sputtering. As-deposited films were exposed to a cold neutron beam with fluences of up to 1.1 x 10(14) cm(-2) and a mean wavelength of 6.9 angstrom. Both irradiated and as-deposited reference samples were characterized with time-of-flight elastic recoil detection analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoemission spectroscopy, and X-ray diffraction. We show that only 1.8 ppm of the B-10 atoms were consumed and that the film composition does not change by the neutron interaction within the measurement accuracy. The irradiation does not deteriorate the film adhesion and there is no indication that it results in increased residual stress values of the as-deposited films of 0.095 GPa. From what is visible with the naked eye and down to atomic level studies, no change from the irradiation could be found using the above-mentioned characterization techniques. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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| 4. |
- Intarasiri, S., et al.
(författare)
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Crystalline quality of 3C-SiC formed by high-fluence C+-implanted Si
- 2007
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 253:11, s. 4836-4842
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Tidskriftsartikel (refereegranskat)abstract
- Carbon ions at 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at 400 degrees C to a fluence of 6.5 x 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a diffusion furnace at atmospheric pressure with inert nitrogen ambient at 1100 degrees C. Time-of-flight energy elastic recoil detection analysis (ToF-E ERDA) was used to investigate depth distributions of the implanted ions. Infrared transmittance (IR) and Raman scattering measurements were used to characterize the formation of SiC in the implanted Si substrate. X-ray diffraction analysis (XRD) was used to characterize the crystalline quality in the surface layer of the sample. The formation of 3C-SiC and its crystalline structure obtained from the above mentioned techniques was finally confirmed by transmission electron microscopy (TEM). The results show that 3C-SiC is directly formed during implantation, and that the subsequent high-temperature annealing enhances the quality of the polycrystalline SiC.
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| 5. |
- Lu, Xuchen, et al.
(författare)
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Heterogeneous Data Source Middleware for Android E-Health Application
- 2012
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Ingår i: 2012 EIGHTH INTERNATIONAL CONFERENCE ON MOBILE AD HOC AND SENSOR NETWORKS (MSN 2012). - 9780769549613 ; , s. 92-99
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Heterogeneous data sources management is a big challenge for complex projects, especially in the situation of sensor net work. The incompatibility of different data sources makes it complicated for a project to modify databases in use or adapt to new sensors. In this paper, we propose a middleware solution to address the problem. The middleware uses an abstract class to shield the differences among heterogeneous data sources and creates a data source service wrapper for each. Both permanent data info and real-time data flows should pass through the middleware during communication of data sources and application. And by implementing a corresponding data source service wrapper, it's very convenient to add a new data source. At the same time, the middleware uses XML to accomplish data mapping and transmission, so as to solve the incompatibility of data sources schema and ensure platform independence. We deployed the middleware to our E-Health project. Our experience has proved the flexibility and extensibility of the middleware.
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| 6. |
- Miao, Y., et al.
(författare)
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Review of Si-based GeSn CVD growth and optoelectronic applications
- 2021
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- GeSn alloys have already attracted extensive attention due to their excellent properties and wide-ranging electronic and optoelectronic applications. Both theoretical and experimental results have shown that direct bandgap GeSn alloys are preferable for Si-based, high-efficiency light source applications. For the abovementioned purposes, molecular beam epitaxy (MBE), physical vapour deposition (PVD), and chemical vapor deposition (CVD) technologies have been extensively explored to grow high-quality GeSn alloys. However, CVD is the dominant growth method in the industry, and it is therefore more easily transferred. This review is focused on the recent progress in GeSn CVD growth (including ion implantation, in situ doping technology, and ohmic contacts), GeSn detectors, GeSn lasers, and GeSn transistors. These review results will provide huge advancements for the research and development of high-performance electronic and optoelectronic devices. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 7. |
- Middeldorp, Christel M., et al.
(författare)
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The Early Growth Genetics (EGG) and EArly Genetics and Lifecourse Epidemiology (EAGLE) consortia : design, results and future prospects
- 2019
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Ingår i: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 34:3, s. 279-300
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Tidskriftsartikel (refereegranskat)abstract
- The impact of many unfavorable childhood traits or diseases, such as low birth weight and mental disorders, is not limited to childhood and adolescence, as they are also associated with poor outcomes in adulthood, such as cardiovascular disease. Insight into the genetic etiology of childhood and adolescent traits and disorders may therefore provide new perspectives, not only on how to improve wellbeing during childhood, but also how to prevent later adverse outcomes. To achieve the sample sizes required for genetic research, the Early Growth Genetics (EGG) and EArly Genetics and Lifecourse Epidemiology (EAGLE) consortia were established. The majority of the participating cohorts are longitudinal population-based samples, but other cohorts with data on early childhood phenotypes are also involved. Cohorts often have a broad focus and collect(ed) data on various somatic and psychiatric traits as well as environmental factors. Genetic variants have been successfully identified for multiple traits, for example, birth weight, atopic dermatitis, childhood BMI, allergic sensitization, and pubertal growth. Furthermore, the results have shown that genetic factors also partly underlie the association with adult traits. As sample sizes are still increasing, it is expected that future analyses will identify additional variants. This, in combination with the development of innovative statistical methods, will provide detailed insight on the mechanisms underlying the transition from childhood to adult disorders. Both consortia welcome new collaborations. Policies and contact details are available from the corresponding authors of this manuscript and/or the consortium websites.
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| 8. |
- Sidén, Johan, 1975-, et al.
(författare)
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Design of High-Directivity Wideband Microstrip Directional Coupler With Fragment-Type Structure
- 2015
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Ingår i: IEEE transactions on microwave theory and techniques. - 0018-9480 .- 1557-9670. ; 63:12, s. 3962-3970
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Tidskriftsartikel (refereegranskat)abstract
- A novel design for a microstrip wideband directional coupler is proposedby using fragment-type structures. The use of a fragment-type structuremay provide satisfactory flexibility and excellent performance. For agiven design space, a fragment-type wideband coupler can be designed byfirst gridding the space into fragment cells and then metallizing thefragment cells selected by a multi-objective optimization searchingalgorithm, such as a multi-objective evolutionary algorithm based ondecomposition combined with enhanced genetic operators. Fordemonstration, a 20-dB wideband microstrip directional coupler isdesigned and verified by test. A 45% bandwidth centered at 2 GHz hasbeen measured in terms of maximum variation of 0.5 dB in the 20-dBcoupling level. In the operation band, the designed coupler hasdirectivity above 37 dB, and a maximum directivity of 48 dB at 2 GHz. Inaddition, some technique aspects related to multi-objective optimizationsearching, such as effects of design space, control of coupling level,and efficiency consideration for optimization searching, are furtherdiscussed. Fragment-type structures may also be used to designhigh-performance wideband directional couplers of tight coupling level.
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| 9. |
- Stolte, W.C., et al.
(författare)
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The K-shell Auger decay of atomic oxygen
- 1997
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - 0953-4075. ; 30:20, s. 4489-4497
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Tidskriftsartikel (refereegranskat)abstract
- Relative photoionization cross sections for O+ and O2+ produced by the Auger decay of a 1s hole in atomic oxygen were measured by using synchrotron radiation between 525 and 553 eV. Energies and quantum defects of the members of the two Rydberg series converging to [1s]2s22p4(4P) and [1s]2s22p4(2P) ionization thresholds were determined. In addition, the 2P and 4P ionization thresholds were calculated from the two Rydberg series. The 182 meV resolution of the monochromator allowed a detailed study over both thresholds revealing evidence for post-collision interaction and allowing a comparison of the ionization continuum above both 2P and 4P thresholds with that of the ionization continuum above the Ar L2 and L3 edges. This comparison indicates that the lifetimes of the Ar(2p) and O(1s) hole states are approximately the same.
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| 10. |
- Wang, Lu, et al.
(författare)
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Design of Chipless RFID Tag by Using Miniaturized Open-Loop Resonators
- 2018
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 66:2, s. 618-626
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, an open-loop resonator with fragment-loading structure is used for the first time in the design of radar cross section-based chipless radio-frequency identification (RFID) tag. By optimizing the distribution of fragment patches in an open loop, a microstrip open-loop resonator can be miniaturized so that the data capacity of the chipless RFID tag designed using such a miniaturized loop resonator can be significantly increased. Moreover, the resonant frequency of the fragment-loaded resonator can be adjusted conveniently by removing or disconnecting some fragment patches, which provides great flexibility for data encoding of the chipless RFID tag. The proposed chipless RFID tag with miniaturized open-loop resonators is designed and tested and can acquire 3.56 bits per resonator and a coding density of approximately 745.1bits/λg 2. Several experimental results validate the proposed design as well as its implementation in a realistic environment.
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